Efficient Light Harvesting in Thick Perovskite Solar Cells Processed on Industry-Applicable Random Pyramidal Textures

Light management is key to high-performance solar cells, particularly to monolithic perovskite/Si tandem solar cells and in real field applications. Random pyramidal textures of commercial Si solar cells (height similar to 2-5 mu m) allow for efficient light harvesting; however, solution processing of conventional perovskite thin films (thickness similar to 0.5 mu m) over these large textures exhibits bad coverage, resulting in shunting paths. In response to this challenge, we present high-efficiency perovskite solar cells (PSCs) processed on replicated industry-applicable random pyramidal textures with a smaller pyramid size of similar to 1-2 mu m. As a first step, we develop planar PSCs with close to micrometer thick perovskite absorber layers that maintain efficient charge carrier extraction by using a Lewis base additive and exhibit a power conversion efficiency of up to 18%. Employing these thick films in textured PSCs with inverted pyramids improves the light management as compared to the planar reference, with the AM 1.5G weighted reflectance being reduced from 9.9 to 5.2%. The reduced broadband reflectance in conjunction with enhanced light trapping increases the current generation by 7.7% relative, which corresponds to 87.3% of the maximum attainable short-circuit current density. In addition, we maintain a high fill factor and open-circuit voltage comparable to that of the planar reference PSC despite the increased surface area of the texture. Thereby, our champion textured PSC exhibits a stabilized power output of 18.7% at maximum power point tracking for 5 min. Finally, the textured PSCs also exhibit improved current generation for all angles of incidence, emphasizing their advantages at realistic irradiation conditions and for bifacial applications.

Automated summary

Light management is crucial for high-performance solar cells, including monolithic perovskite/Si tandem solar cells. This study presents high-efficiency perovskite solar cells processed on industry-applicable random pyramidal textures. These textured solar cells demonstrate improved light management compared to planar cells, with reduced reflectance and enhanced light trapping. Furthermore, the textured cells maintain high fill factor and open-circuit voltage, and exhibit improved current generation for all angles of incidence, making them advantageous for realistic irradiation conditions and bifacial applications.